text: /*
   * Copyright 2015 Google Inc.
   *
   * Use of this source code is governed by a BSD-style license that can be
   * found in the LICENSE file.
   */
  
  #include "SkAndroidCodec.h"
  #include "SkBitmapRegionCodec.h"
  #include "SkBitmapRegionDecoderPriv.h"
  #include "SkCodecPriv.h"
  #include "SkPixelRef.h"
  
  SkBitmapRegionCodec::SkBitmapRegionCodec(SkAndroidCodec* codec)
      : INHERITED(codec->getInfo().width(), codec->getInfo().height())
      , fCodec(codec)
  {}
  
  bool SkBitmapRegionCodec::decodeRegion(SkBitmap* bitmap, SkBRDAllocator* allocator,
          const SkIRect& desiredSubset, int sampleSize, SkColorType prefColorType,
          bool requireUnpremul) {
  
      // Fix the input sampleSize if necessary.
      if (sampleSize < 1) {
          sampleSize = 1;
      }
  
      // The size of the output bitmap is determined by the size of the
      // requested subset, not by the size of the intersection of the subset
      // and the image dimensions.
      // If inputX is negative, we will need to place decoded pixels into the
      // output bitmap starting at a left offset.  Call this outX.
      // If outX is non-zero, subsetX must be zero.
      // If inputY is negative, we will need to place decoded pixels into the
      // output bitmap starting at a top offset.  Call this outY.
      // If outY is non-zero, subsetY must be zero.
      int outX;
      int outY;
      SkIRect subset = desiredSubset;
      SubsetType type = adjust_subset_rect(fCodec->getInfo().dimensions(), &subset, &outX, &outY);
      if (SubsetType::kOutside_SubsetType == type) {
          return false;
      }
  
      // Ask the codec for a scaled subset
      if (!fCodec->getSupportedSubset(&subset)) {
          SkCodecPrintf("Error: Could not get subset.\n");
          return false;
      }
      SkISize scaledSize = fCodec->getSampledSubsetDimensions(sampleSize, subset);
  
      // Create the image info for the decode
      SkColorType dstColorType = fCodec->computeOutputColorType(prefColorType);
      SkAlphaType dstAlphaType = fCodec->computeOutputAlphaType(requireUnpremul);
      SkImageInfo decodeInfo = SkImageInfo::Make(scaledSize.width(), scaledSize.height(),
              dstColorType, dstAlphaType);
  
      // Construct a color table for the decode if necessary
      SkAutoTUnref<SkColorTable> colorTable(nullptr);
      SkPMColor* colorPtr = nullptr;
      int* colorCountPtr = nullptr;
      int maxColors = 256;
      SkPMColor colors[256];
      if (kIndex_8_SkColorType == dstColorType) {
          // TODO (msarett): This performs a copy that is unnecessary since
          //                 we have not yet initialized the color table.
          //                 And then we need to use a const cast to get
          //                 a pointer to the color table that we can
          //                 modify during the decode.  We could alternatively
          //                 perform the decode before creating the bitmap and
          //                 the color table.  We still would need to copy the
          //                 colors into the color table after the decode.
          colorTable.reset(new SkColorTable(colors, maxColors));
          colorPtr = const_cast<SkPMColor*>(colorTable->readColors());
          colorCountPtr = &maxColors;
      }
  
      // Initialize the destination bitmap
      int scaledOutX = 0;
      int scaledOutY = 0;
      int scaledOutWidth = scaledSize.width();
      int scaledOutHeight = scaledSize.height();
      if (SubsetType::kPartiallyInside_SubsetType == type) {
          scaledOutX = outX / sampleSize;
          scaledOutY = outY / sampleSize;
          // We need to be safe here because getSupportedSubset() may have modified the subset.
          const int extraX = SkTMax(0, desiredSubset.width() - outX - subset.width());
          const int extraY = SkTMax(0, desiredSubset.height() - outY - subset.height());
          const int scaledExtraX = extraX / sampleSize;
          const int scaledExtraY = extraY / sampleSize;
          scaledOutWidth += scaledOutX + scaledExtraX;
          scaledOutHeight += scaledOutY + scaledExtraY;
      }
      SkImageInfo outInfo = decodeInfo.makeWH(scaledOutWidth, scaledOutHeight);
      if (kGray_8_SkColorType == dstColorType) {
          // The legacy implementations of BitmapFactory and BitmapRegionDecoder
          // used kAlpha8 for grayscale images (before kGray8 existed).  While
          // the codec recognizes kGray8, we need to decode into a kAlpha8
          // bitmap in order to avoid a behavior change.
          outInfo = SkImageInfo::MakeA8(scaledOutWidth, scaledOutHeight);
      }
      bitmap->setInfo(outInfo);
      if (!bitmap->tryAllocPixels(allocator, colorTable.get())) {
          SkCodecPrintf("Error: Could not allocate pixels.\n");
          return false;
      }
  
      // Zero the bitmap if the region is not completely within the image.
      // TODO (msarett): Can we make this faster by implementing it to only
      //                 zero parts of the image that we won't overwrite with
      //                 pixels?
      SkCodec::ZeroInitialized zeroInit = allocator ? allocator->zeroInit() :
              SkCodec::kNo_ZeroInitialized;
      if (SubsetType::kPartiallyInside_SubsetType == type &&
              SkCodec::kNo_ZeroInitialized == zeroInit) {
          void* pixels = bitmap->getPixels();
          size_t bytes = outInfo.getSafeSize(bitmap->rowBytes());
          memset(pixels, 0, bytes);
      }
  
      // Decode into the destination bitmap
      SkAndroidCodec::AndroidOptions options;
      options.fSampleSize = sampleSize;
      options.fSubset = &subset;
      options.fColorPtr = colorPtr;
      options.fColorCount = colorCountPtr;
      options.fZeroInitialized = zeroInit;
      void* dst = bitmap->getAddr(scaledOutX, scaledOutY);
  
      // FIXME: skbug.com/4538
      // It is important that we use the rowBytes on the pixelRef.  They may not be
      // set properly on the bitmap.
      SkPixelRef* pr = SkRef(bitmap->pixelRef());
      size_t rowBytes = pr->rowBytes();
      bitmap->setInfo(outInfo, rowBytes);
      bitmap->setPixelRef(pr)->unref();
      bitmap->lockPixels();
      SkCodec::Result result = fCodec->getAndroidPixels(decodeInfo, dst, rowBytes, &options);
      if (SkCodec::kSuccess != result && SkCodec::kIncompleteInput != result) {
          SkCodecPrintf("Error: Could not get pixels.\n");
          return false;
      }
  
      return true;
  }
  
  bool SkBitmapRegionCodec::conversionSupported(SkColorType colorType) {
      // FIXME: Call virtual function when it lands.
      SkImageInfo info = SkImageInfo::Make(0, 0, colorType, fCodec->getInfo().alphaType(),
              fCodec->getInfo().profileType());
      return conversion_possible(info, fCodec->getInfo());
  }
  